Jacks are basically portable tools for lifting heavy loads through relatively short distances and there are various kinds of jacks commonly in operation including screw jacks, rack and lever jacks and hydraulic jacks.
A large portion of the population is familiar with jacks in view of their historical association with vehicles such as the automobile. Jacks for automobiles have taken many forms and at one time "bumper" jacks were the most common, i.e. those jacks which lift one corner of a vehicle through operative association with a bumper. However bumpers on most vehicles are no longer being used as attaching points for jacks and there is a distinct move to jack vehicles through a cooperative association of a jack with touch or jack points provided by the manufacturer and usually accessed from the side of the vehicle.
Conventional touch point jacks used by garage service lifts must be positioned underneath the vehicle making it both awkward to operate and this obliges the operator to come into direct contact with the terrain the vehicle happens to be positioned on.
Further, there is a tendency for existing jacks to require enlarged base plates since the jacking process usually causes the jack to move off the vertical. If the jack leans too much, the situation becomes dangerous to the operator of the jack.
Accordingly, there is a need for a jack which is easily placed into location and contact with the appropriate touch point and which moves itself automatically into an alignment wherein the weight of the car being lifted is through the touch point contact or bracket or the jack and the base support.
Further, a jack which lifts the vehicle from the side rather than from underneath enhances the ease of locating the jack and the safe operation by the operator.
Vehicle jacks of the cantilever type are known and exemplified in U.S. Pat. Nos. 4,194,725, Mar. 25, 1980 to ERSCHENS; 4,289,300, Sept. 15, 1981 to WEISSER ET AL and Re. 30,640, June 9, 1981 to KEILHOLZ.
However, these jacks are not suitable for selective operation with electric motors of a type which maintain the general compactness of the device including eliminating translational movement between exposed elements which could be detrimental from a safety point of view.